This invention relates to a hydroelectric machine including a tube-type hydraulic turbine or pump having a bladed wheel which carries adjustable blades, rotates about a horizontal axis and is connected to a shaft which extends into a guide blade lattice hub, and an electrical machine which surrounds the bladed wheel and has a rotor secured to an annular rim in which the external ends of the adjustable wheel blades are pivotably mounted.
A hydroelectric machine of this kind is disclosed in Swiss Pat. No. 347,253. In that proposal, the rotating machine set is supported radially by three bearing arrangements. One of these bearing arrangements is associated with the rotating unit formed by the rotor and the rim and comprises a running drum or barrel which is secured to the rim and cooperates with sleeve bearing segments which are distributed around its periphery. The other two bearing arrangements are associated with the shaft at its free and bladed wheel ends, respectively, and each of these arrangements consists of a conventional sleeve bearing. The rotating unit and the bladed wheel were supported separately with the intent of relieving the wheel bearings of the weight of the rotating unit, and thus insuring reliable adjustability of the blades under all operating conditions. However, all attempts to construct this hydroelectric machine have in the end failed because the use of sliding surface bearing segments to support the rotating unit is problematical. The running drum is large and may have a diameter of 2 to 12 meters, and this makes it very difficult to manufacture the bearings with the required tolerances. Moreover, with such a large diameter, the unavoidable deformation of the rim attributable to dead weight, centrifugal forces and temperature fluctuations must also be taken into account. In addition, high peripheral speeds (e.g. 150 meters per second) at the rim must be accommodated. Finally, the bearing arrangement is difficult to assemble, and, during operation, it does not maintain concentricity between the rotating unit and the bladed wheel and thus causes additional forces to be imposed on the machine components.